Making tone in tone effects in woolen fabrics



- Patented Nov. 10, 1931 a I UNITED STATES PATENT-OFFICE,

BUbOLF BRAUCmYER, OI GRUNBERG, GERMANY, ASSIGNOR T DEUTSCHE WOLLEN- WAREN-MANUFAOKUR AKTIENGESELLSCHAFT, OF GR'UNTBERG, SILESIA, GERMANY TONE IN TONE EFFECTS IN WOOLEN FABRICS v No Drawing. Application filed October This invention relates to a method for producing tone in tone (deux tone) effects in woolen fabrics.

'-It is known to increase the adsorbability of wool for dyes by treating the wool fiber with certain chemicals and to use this fact for obtaining tone in tone effects in woolen fabrics by treating one part of the undyed wool yarn with cold, diluted sodium hydroxide solution or other strongly alkaline reacting substances, weaving the treated wool yarn together with untreated yarn and dyeing the obtained fabric in one. single dye bath with the usual acid wool dyes. The pretreated yarn then adsorbs greater amounts of dye in shorter time, than the untreated yarn, t ereby obtaining a good tone in tone effect in the fabric.

This method for producing tone in tone effects has however not found general application, as the pretreatment of. the wool with strongly attacking chemicals hurts the wool fibre considerably and even dissolves it partly, thereby chan ing the physical properties of the wool. bus for example a wool treated as above described loses at least 40- of its strength and extensibility and is therefore not suitable for use.

According to my invention I obtain strongly contrasting tone in tone effects-in woolen fabric without hurting the wool fibre to such an extent as above, b pretreating the wool for a short time with so utions of salts, as for example sodium phosphate, sodium borate and the like hydrolytically decomposed, whereby the adsorbability for dyes of the wool fiber is considerably increased. The hydrolytic decomposition referred to in the foregoing sentence results from a double decomposition of the salt and the water into acid ions and hydroxyl ions, the hydroxyl ions being-slightly more numerous than the acid ions thus keeping the solution basic to a small degree so as not'to injure or dissolve the wool. Compared with the known methods the action of the salts upon the wool fiber is so'feeble, that an injury of the wool can scarcely be noticed even by microscopical examination. The change of the wool isso small, that good tone in tone effects are not'obtained, when dyeing usual dyeing conditions.

adsorbability for dyes.

25, 1927, Serial No. 228,694, and in Germany October 8,- 1927.

a fabric made from untreated and pretreated wool with the usual acid wool dyes under the I have found that dyes which are seldom or never used for dyeing wool due to their varymg-afiinity for the wool fiber under different conditions of dyeing, i. e., temperature variation, concentration of solution, etc.', are well adapted forproducin contrasting tone in tone effects in woolen abrie when employed with wool pretreated by my method. Thus Y and polyazo dyes es-l pjecially those known in thetrade as Benzo for example the diazo ight dyestuffs, which are otherwise generally used for dyeing cotton, produce, in a comparatively strongly acid dyeing bath, great differences in color upon untreated and feebly pretreated wool Whereas these dyes are completely developed only in presence of 610% sulfuric acid by a boiling during several hours, a smaller addition of sulfuric acid for example 2% ducing tone in tone effects, as the pretreated wool fiber adsorbs and binds the dye easily.

Example I is already sufiicient for pro-- The loose wool or the wool yarn is boiled for about one hour in a bath containing 6% sodium phosphate in order to increase its The pretreated wool fiber is spun together with untreated wool fiber and then woven or the pretreated wool yarn is woven together with untreated yarn to a fabric having the desired tone in tone design and the obtained fabric is dyed with 0.2% Benzo Light red 8 B L color index number 278, 4% acetic acid and 10% Glauberssalt. The fabric enters this dyein bath at temperatures between 35 and 40 .and the bath is then slowly brought to boil. For the increased dye adsorbability of, the pretreated wool the bath is quickly exhausted, thusonly a short boiling period being necessary. It is to be understood that the percentages referred to.in this and the following example relate to the weight of the woolen material dyed;

The obtained dyed fabric is especially proof against boiling, which is generally not the case with fabric dyed with the usual acid wool dyes. When tone in tone designs are made according to my invention it is therefore not to be feared that the dfierences in tone between pretreated and untreated wool 5 are equalized during a longer boiling period.

It is further also possible to make use of .my invention in those methods, where the dye adsorbability of certain parts of a fabric is increased by printing chemical substances upon the fabric. Until now one has used for this purpose strongly alkaline reacting printing pastes containing for example 450 gr. sodium h droxide solution of 40 B., 125 gr. water, 5 gr. glycerine, 250

gr. tragacanth (65: 1000) and 100 gr. British gum. These pastes are however real solvents for the wool and have therefore not been used, as they injure the wool fibre considerably.

However when using the above mentioned dye groups one obtains, by printing the fabric with a paste containing for example 150 gr. sodium borate and 850 gr. tragacanth solution and steaming the printed texture for a short time, such an increased dye adsorbability of the rinted parts, without injuring the wool fibers, that wonderful tone in time effects are obtained with a single dye Example 11 The fabric is printed with a paste containing 150 parts sodium borate and 850 parts tragacanth solution, then steamed during 10 to 15 minutes, rinsed and dyed in a bath containing 0.5% polyazo dyestufi and 2% sulfuric acid and having a temperature of 30 C. at the start.

I claim:

1. A method for producing tone in tone 9 effects in woolen fabrics comprising the steps of treating those parts of the fabric, which are to have the deeper tone, with solutions of hydrolytically decomposed salts and dyeing the fabric with azo dyes having accord.- ing to the dyeing conditions a varying afiinity for the wool fibre.

2. A method for producing tone in tone effects in woolen fabrics comprising the steps of treating those parts of the fabric, which are to have the deeper tone, with solutions of hydrolytically decomposed salts and dyeing the fabric with dyes containing at least two azo groups and having according to the dye- }ing conditions a varying affinity for the wool bre.

In testimon whereofi-I aflix my si ature.

R OLF "BRAUCKME R. 

